There currently exist two general types of premium golfballs: a "three-piece" ball which comprises a spherical molded center, having an elastomeric thread-like material wound around it, covered with either a thermoplastic or thermoset material; and a "two-piece" ball which comprises a spherical molded core covered with a thermoplastic material. The material used to mold the three-piece centers and the two-piece cores has traditionally been a thermoset rubber, for example, polybutadiene rubber. As with any thermoset material, however, there are major disadvantages, such as the inability to recycle scrap materials and the need for complex multistep manufacturing processes. Of course, three-piece balls and two-piece balls are by their very nature more complicated and costly to manufacture than the long sought after one-piece golfball, which has yet to be successfully demonstrated except for limited flight golfballs.
In an effort to overcome the deficiencies of the traditional thermoset three-piece centers and two-piece cores, and in the quest to produce a one-piece golfball, attempts have been made to utilize certain thermoplastic materials in the molding of such centers, cores and one-piece balls, but with limited success. For example, U.K. Patent Application 2,164,342A describes moldable compositions comprising ionic copolymers (or potentially ionizable acid copolymers) blended with certain thermoplastic materials such as a polyester block copolyamide, a polyether copolyamide, a copolyester and the like. Those compositions are said to be useful as three-piece centers, two-piece cores and one-piece solid golfballs, but they lack, e.g., durability. Therefore, there still exists the need for a material that is thermoplastic, yet resilient and durable enough, and imparting adequate compression, to be useful as a three-piece center, two-piece core and a one-piece golfball.